De-solvation of metal complexes to construct metal-organic framework glasses

Structural fine-tuning is an important challenge in the chemistry of metal-organic framework (MOF) glasses. Current approaches of thermally/mechanically-induced vitrification are limited for azolate/cyanide-based crystalline MOFs, while other MOF crystals usually decompose before melting or amorphize upon milling instead of forming stable glasses. Here, we developed a general method, “de-solvation” of solvated metal-ligand complexes to gently prepare MOF glasses by demonstrating 12 ligands of varying lengths, shapes, side- and coordination-groups (carboxylate/pyridyl/azolate). Hydrogen-bond networks of the metal complexes offer the spatial arrangements of metal-ligand units, thus guiding the glass formations during de-solvation. The prepared glasses have high structural diversities with tunable pores (sizes and modifications) and dimensionalities (one to three), and high glass-forming abilities with wide transition temperature windows from 120 to 280 °C, affording grain-boundary-free/transparent monoliths under heating without pressure.